Nucleation in recording and development

ABSTRACT

The image-recording medium comprises an actinic ray sensitive material and a metallic compound which acts as a nucleationinducing medium dispersed in a film-forming vehicle and preferably coated on a substrate. The actinic ray sensitive material is preferably zinc oxide, while the nucleation-inducing medium is preferably a copper-containing compound. The process is directed to forming and using the medium and comprises dispersing the sensitive material in the vehicle with the aid of a vehicle solvent and dispersing the metallic compound in the mixture with the aid of a solvent compatible with the vehicle solvent, followed by forming the mixture into a film. The medium is imagewise exposed, followed by development by imagewise disposition of metal from metal vapor, in accordance with nucleation sites produced by exposure.

' United States Patent Kaspaul et al. [4 May 2, 1972 541 NUCLEATION IN RECORDING AND 3,245,786 4/1966 Cassiers et al. ..96/1 DEVELOPMENT 3,317,409 5/1967 Kaspaul et al. .204/l8 3,462,762 8/l969 Kaspaul et al. .....346/74 Inventors Alfred? 13 1: Erika Kaspaul, both 3,467,603 9/1969 Brown 252/501 f Malibu, Cahf- 3,494,766 I 2/1970 lwai et al. ..96/1.8 [73] Assignee: Hughes Aircrafi Company Culver City 3,515,550 6/1970 l-le1decker ..96/l.8

' Cahf' Primary Examiner-Charles E. Van Horn [22] Filed: July 7, 1969 AssisrantExaminer-John C. Cooper, lll A 1 No 839 271 Attorney-James K. Haskell and Allen A. Dicke,Jr.

Related US. Application Data [57] ABSTRACT The image-recording medium comprises an actinic ray sensi- [63] fggg s z g of Sept tive material and a metallic compound which acts as a nucleaa an one tion-inducing medium dispersed in a film-forming vehicle and preferably coated on a substrate. The actinic ray sensitive [52] US. Cl. ..96/1.8, 96/1 R, 96/ 1.5, material is preferably Zinc oxide, while the nuc|eafion induc 96/27 252/501 g 21 ing medium is preferably a copper-containing compound. 51 1111. C1. .f. ..G03g '13/22, 603 5/06 The p o e s is directed to forming and using the medium and 58 Field of Search ..96/1.5, 1, 1.8, 27; 252 501; comprises dispersing the sensitive material in the vehicle with 106/296 the aid of a vehicle'solvent and dispersmg the metallic compound in the mixture with the aid of a solvent compatible with the vehicle solvent, followed by forming the mixture into' a [56] References Cited film. The medium is imagewise exposed, followed by develop- UNITED STATES PATENTS ment by imagewise disposition of metal from metal vapor. in 3 197 307 7/1965 Bl k t l 96/1 accordance with nucleation sites produced by exposure.

a ee a 3,198,632 8/1965 Kimble et al ..96/l 13 Claims, 5 Drawing Figures Beam Source: Ions, Photons, Electrons Vopor source IPATENTEDMAYE I972 3. 660-, 087 SHEET 10F 2 Beam Source: Ions, Photons, Electrons Developed Image Recording medium Fig. 1.

Alfred FKospoul, Erika EKospdul,

AHenA.Dike,dr.,

AGENT.

INVENTORS.

NUCLEATION 1N RECORDING AND DEVELOPMENT CROSS- REFERENCE This application is a continuation-in-part of SerfNo. 582,079, filed Sept. 26, 1966 by Alfred F. Kaspaul and Erika E. Kaspaul for IMAGE RECORDING AND DEVELOP- MENT, now abandoned.

BACKGROUND,

1 Field of the Invention The medium is actinic-ray sensitive and its latent images are rendered visible by selective deposition of metal from the vapor state, in accordance with the latent image content. The process is the procedure of preparing the medium, particularly with the employment of plural solvents,'and of employing the medium with exposure and metal vapor development.

2. The Prior Art I Theselective deposition of materials, particularly metals, upon a preconditioned or what may be referred to as a prenucleated'recording medium," is known. Such selective deposition processes have employed various means for providing a prenucleated image which is invisible and latent. Thus, such prenucleated images have been formed by scanning a surface of a substrate with an electron or ion beam or by exposing the surface to a light image of the desired pattern.

In U.S. Pat. No. 3,140,143, issued to the instant inventors, the formation of such prenucleated images is achieved by depositing at'least trace amounts of an aqueous liquid on preselected portions of the surface of a substantially inert, anhydrous solid substrate which has an inorganic metal compound as a part of its surface. Such a surface is typically pro- .vided according to this patent by means of a thin film consisting of zinc oxide incorporated into a resinous binder, such as a copolymer of butadiene and styrene. The latent image on such a substrate surface is formed by depositing water, for example, in the pattern desired upon such surface. The image is then developed by exposing this surfaceto vapors of a metal in a vacuum chamber, the metal atoms being selectively deposited upon and in accordance with the aqueous liquid pattern.

Similarly, in US. Pat. No. 3,235,398, the instant inventors have disclosed recording media and processes for recording thermal or infrared information wherein substrates, such as mica, baryta paper, andpolyethylene terepththalate films are coated with finely divided zinc oxide in an organic binder. On the surface of this coating, a material such as nickel, silver, copper, cuprous' chloride, bismuth, or bismuth oxide is vacuum vapor deposited. Such deposited materials, according to this patent, serve topre-sensitize the surface of the recording medium by forming nucleation sites which aid in the selective deposition of vapor during development of an infrared image focused on the surface of the recording medium. In this system, it is necessary to simultaneously or substantially immediately expose the recording medium to the development vapor with exposure to the infrared image, since the infrared image appears to have no lasting effect upon the recording medium.

As noted previously, another procedure for obtaining the requisite pattern of prenucleated areas is by scanning or otherwise exposing the surface of a substrate with electrons, ions or photons and, thereafter, developing the latent image thus formed by exposing the surface to metallic vapor so that the metal atoms are selectively deposited and grow upon and in accordance with theprenucleated pattern. Such a process is described by the present inventors as applicable for fabricating microcircuits in a paper, titled Application of Molecular Amplification to Microcircuitry," published in the 1963 Transactions, Tenth National Vacuum Symposium, American Vacuum Society. The process described therein, as well as the phenomena involved in the present invention, are called molecular amplification" because the nucleated sites selec" tively capture thousands of atomsor molecules of the depositing or condensing material. The term molecular amplification describes the collection effectiveness of each nucleation center which captures a much larger number of atoms or molecules from the surrounding vapor than they contain themselves.

Thus, invisible nucleation centers, of the present medium, established by an actinic ray exposure such as by electrons, ions, molecules or photons, containing about atoms per cm (which corresponds to about 0.01 monolayer), become visible by collecting a total of about 10 atoms per cm. This means that each atom in a nucleation center has captured at least 10,000 atoms from the incident vapor (or molecular beam, which phrase is customarily used to describe material vapor directed toward the substrate surface as a vapor stream or beam). Prior to the present invention, the overall collection efficiency was strictly controlled by nucleation centers resulting from interactions of electrons and photons with the outer most surface layer on a chosen substrate. This very thin layer is produced either by predeposition of an electron or photon sensitive compound, such as described previously, or by having a gaseous compound in contact with the substrate at all times, such as described in US. Pat. No. 3,378,401. Because of the very small cross-section of thin surface layers interacting with photons or electrons, a large portion of the incident radiationis lost into the subsurface.

According to the present invention, the incident photons or electrons are at first intercepted by a photon or electron sensitive material, such as zinc oxide or other suitable compounds, which is of sufiicient thickness to absorb most of the incident radiation. It is assumed that this results in an energy transfer from the irradiated zinc oxide to a nucleation-inducing compound which is intimately dispersed with the zinc oxide in a suitable binder. It is further assumed that this transfer results in the generation and subsequent migration of metal ions to the surface'nucleation sites where neutralization by trapped electrons produces a stable nucleation cluster. The contribution by the volume or bulk of the recording medium to the overall gain of the deposition process is achieved by incorporating a nucleation-inducing agent in a film-forming binder in which is dispersed a material sensitive to electrons, ions or photons. The result is a net gain of two to three orders of magnitude, as compared to films of the prior art depending solely upon surface phenomena. In contrast with prior art recording media, the recording media of the present invention unexpectedly obtains substantiallythe same efiect upon condensation of atoms and molecules from the vapor phase thereof for a substantially lesser amount of initiating (exposure) energy. Stated another way, the recording media of the present invention unexpectedly obtains a dramatically increased condensation efficiency-Le, by twoto three orders of magnitudefor the same amount of initiating exposure energy.

SUMMARY second solvent, a metal compound which acts as a nucleation inducing compound. The preferred actinic ray sensitive material is actinic ray sensitive zinc oxide and the preferred metal compound is a copper salt.

The process of producing the nucleation-recording medium comprises dispersing the actinic ray sensitive material in the film-forming vehicle with a first solvent which dissolves the film-forming vehicle, and dispersing in the film-forming vehicle, with the aid of the second solvent, the nucleation-inducing metal compound, the second solvent being compatible with the first solvent, and forming a film followed by substantial evaporation of the solvents to form the medium.

The present invention has as its principal object the provision of a new and improved medium for photon and/or electron beam recording processes. Among other objects and advantages of the present invention are: the provision of new and improved materials'capable of being sensitized or nucleated for use in the process of image or signal recording; the provision of new and improved nucleating recording media for use in the process of selective deposition of atoms and molecules; the provision of new and improved recording media on which latent nucleation images may be rendered visible; the provision of new' andimproved recording mediapermitting the rapid recording and development of information using selective deposition of atoms and molecules and the correspondingly rapidreading out of information so recorded; the provision of new and improved recording media on which images or information in the form of invisible latent patterns may be formed and rendered visible by selective vapor deposi- -tion; and the provision of new and improved recording media for rapidly producing permanent, visible patterns of predetermined geometries or records of information.

Briefly, these and other objects of the invention are achieved by providing novel recording materials or media which permit the attainment of additional or more effective sensitization effects for molecular amplification from within the bulk of the recording medium.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic illustration of the process of the invention in which a scanning beam is utilized to establish a latent image of nucleation centers;

FIG. 2 is a schematic illustration of the process of the invention inwhich a flood beam and image-defining mask areutilized to establish a latent image of nucleation centers;

FIG. 3 is a schematic perspective view of a substrate with a developed image area thereon;

FIG. 4 is a schematic illustration of an embodiment of the invention in a rapid and a continuous tape recording and/or optical reading apparatus; and

FIG. 5 is a schematic illustration of another embodiment'of the invention in a rapid recording and reading-out apparatus.

DESCRIPTION OF THE PREFERRED EMBODIMENTS It should be understood that broadly the present invention relates to the formation of an image on a'recording medium which image is initially not necessarily visible, but may be rendered visible and read electronically. Such images are, therefore, hereinafter referred to as latent. Furthermore, the term image, as used herein, is intended to mean the entire area of the surface of the recording medium or any portion less than the whole thereof, including patterns which visually impart information (such as words or pictures) or which patterns perform some esthetic or utilitarian function (such as a decorative design or electrically conductive paths for so-called printed circuitry).

More particularly, the invention relates to the formation of image areas by the process of exposing a recording medium to electrons, ions or photons whereby the exposed areas of the medium appear to function as what may be called nucleation sites on which one or more materials may be selectively deposited from the vapor phase thereof and thus rendered visible or otherwise useful. The exposure process is referred to hereinafter as selective nucleation, by which is meant the establishment of such nucleation sites in or on the recording medium, which nucleation sites are capable of attracting vast numbers of atoms or molecules or other particle forms of a vaporous material to which therecordin'g medium is exposed. This nucleation is selectively established in response to impingement of the recording medium by electrons, ions or photons. The invention relates especially to new and exceptionally efficient recording medium materials capable of forming such nucleation sites in response to exposure by light or by a bombarding and scanning electron or ion beam. In general,

these nucleation sites are developed (rendered visible or otherwise useful) by the vapor-deposition of metals, although the practice of the invention is by no means so limited since the novelty and usefulness of the present invention depends more upon the recording medium materials than upon the developer materials.

As mentioned previously, the use of the medium of the present invention involves twoprincipal steps, the first of which is exposure of a nucleatable recording medium to electrons, ions or photons, which may be in the form of a scanning beam or a mask-formed pattern thereof whereby a latent image is established on or in the medium corresponding to that formed by the beam or pattern of such energy. The latent image is apparently constituted by nucleating sites selectively established in accordance with the areas of the recording medium impacted by the electrons, ions or photons. These latent images are termed nucleating sites herein because of their apparent ability to enhance and promote the growth thereat of atoms or molecules of the vapor developer material while other unexposed areas of the recording medium do not appear to permit such deposition or growth to any appreciable extent. The second step in the process is the development of the latent image comprising these nucleating sites so as to render this image visible or otherwise useful, which step is accomplished by exposing the surface of the recording medium to a developer material in the vapor phase thereof. This material deposits and grows (nucleates) on and from the latent image nucleating sites to form a visible image or pattern which is bonded to the recording medium thereby remaining permanently in place. The image thus developed may be a conductive pattern as for an electrical circuit, or it may be pictorial or textual or symbolic, in which case a permanent recording is obtained which may be immediately viewed or read and then stored for subsequent reading or viewing. Because recordings made according to the process of the invention may be extremely-small without loss of detail, a great amount of information may be recorded on small area tapes which need occupy only a small volume, thus making the invention extremely useful for recording for later recall or use large masses of information. Since the process'is extremely rapid, taking less than a second to record and to develop a fully usable copy, it offers distinct advantages over present photographic techniques inuse for this purpose. The absence of corrosive liquids, time-consuming chemical development processes also enhances'the usefulness of the present invention over present conventional photographic processes and also permits the attainment of an immediately readable copy upon recording. This latter aspect offers a distinct advantage in information-handling systems where one is usually compelled to wait while a tape is being held to permitprintinga la I a teletype or typewriter currently employed in such systems.

Thus, the invention permits one to have a continuously moving tape upon which information is being recorded and which information can be directly and immediately read or utilized.

RECORDING As previously explained, recording media prepared according to the invention and described in greater detail hereinafter may be exposed to have a latent image of nucleating sites by being impinged by ions, electrons or photons, which comprise actinic rays.

The electrons, ions or photons may be formed in relatively narrow actinic ray beams and caused to scan the recording medium to establish the desired pattern of nucleation centers. Such a scheme is depicted in FIG. 1 where a beam source 2 is provided to generate a beam of ions, electrons or photons with which to scan a recording medium'4 according to the invention. The beam 3 is capable of being deflected orthogonally, as indicated by the X-Y axes, by means of apparatus. and techniques well-known in the art. A beam of light or photons may be generated and caused to scan the recording medium 4 by a cathode ray tube, particularly of the type known as a flypelled to waid ing-spot scanner. The electron beam may be generated by any of the well-known electron gun devices used in cathode ray tubes, for example. In the cases where scanning and nucleation are accomplished by ions or electrons, it will be appreciated that beams of these energy forms must be generated in vacuo and the recording medium 4 will also needbe exposed thereto in vacuo. The requisite vacuum chamber 6 is indicated in FIG. 1 by dotted lines, since it may be of any design or structure to accomplish the purpose of permitting an evacuated volume to be established and maintained therewithin. Normally, since it will be desirable to insert and remove recording media (either discretely or continuously), parts (not shown) for such purposes ,will be provided in the vacuumforming structure. Likewise not shown but desirable are means for pumping down or evacuating the chamber 6 whenever the desired vacuum therewithin is lost, as by opening the chamber to remove recording media. It will also be understood that since the recording media of the present invention are usually light-sensitive, the recording step should be carried out in a light-tight or dark box which excludes light of the frequency or frequencies to which the recording media are sensitive. In the case of optical or photon exposure, however,

it is not necessary to provide-the recording .mediumin a vacuum, except for the development step.

In FIG. 2, another arrangement is shown for accomplishing the recording or exposure by electrons, ions, or photons, but without requiring the formation thereof into narrow beams and the line-by-line (or point-by-point) scanning of the recording medium thereby. In this embodiment, an imageforming member or mask, difierent portions of which are transmissive and non-transmissive to electrons, ions or photons, is provided adjacent a recording medium according to the invention so as to intercept some or all of a flood or blanket beam of electrons, ions orphotons. Thus the recordingmedium will be exposed or sensitized in a pattern corresponding to the transmissive and non-transmissive portions of the image-forming member or mask. This mask may be in the form of a non-transmissive plate having pattern of imagedefining cut-out portions. It may also be in the form of a information, such information will be readily visible to the eye.

may be controllably opened or connected to the sensitization photographic negative or the like. In these two instances,

penetration through the image-forming member by unintercepted electrons, ions or photons is contemplated. However, the terms transmissive" and fnon-transmissive aroused-in their very broadest sense to include-not only passage through the image-forming member but the interception or non-interception by reflection or absorption of electrons, ions or.

photons as well. Thus, any document which is capable of selectively reflecting light, for example, in accordance with the characters or'patterns thereon, may also be used to determine the pattern of the energy impinging on the recording medium so that a replica of the document may be ultimately reproduced thereon in accordance with the invention. Again, it will be appreciated that electronic and ionic exposure will be carried out in vacuo while photon exposure may be carried out in a non-evacuated, but light-tight chamber. By lighttight, we means at least the exclusion of light of the frequency'or frequencies to which the recording medium is sensitive.

DEVELOPMENT As a result of the impingement of electrons, ions or photons on the recording substrate, the surface thereof is provided with a latent image comprising a number of nucleation sites the pattern of which corresponds to the indicia to be reproduced. When such a latent image is exposed to the vapor of a metal, for example, atoms or molecules from the vapor are selectively attracted to and retained in place only by the nucleated areas comprising the latent image. By the invention, it is calculated that each atom in a nucleating site may capture as many as 10,000 atoms from the vapor. Thus a quantitatively significant deposition of the material of the vapor upon the recording medium in any desired pattern may be achieved. Where the deposition pattern represents symbolic or pictorial chamber to permit the vapor to be introduced thereinto. The exposed recording medium may also be transferred to a separate chamber for development by exposure to the vapor.

As noted, it is possible to expose a sensitized recording medium to the development vapor or molecular beam during the exposure step so that the latent image is developed as it is being formed. However, it may be preferable to develop the latent image sequentially with respect to its formation and after it has been completely formed. In general, it has been found convenient to provide an e vacuable chamber in which the recording medium is disposed and containing as well an electron or ion source and a vapor source which is controllably isolated from the chamber interior. After evacuating the chamber, the latent image is formed by electrons or ions. The vapor source may be activated during this step and, thus, ready to deliver vapor to the chamber. After the latent image is formed, the vapors are then admitted to the chamber interior and the now-sensitized recording medium exposed thereto.

Because of the ease and cleanliness characteristic of vapor deposition processes, development by exposure of the sensitized recording media to vaporous development materials is preferred. However, it is also possible to develop the latent image by immersing or otherwise exposing the media in a plating solution, particularly of the electroless type. Such electroless plating processes are well-known and need not be described in greater detail.

In a continuous process of exposure and development, there appears to be a simultaneous occurrence of exposure and development. In this process, a vapor beam is directed toward a temperature-controlled substrate. Upon establishing the proper conditions, well-known in the art of vapor deposition, at which equilibrium exists on the recording substrate surface, the number of atoms leaving the surface equals the number of incident atoms. If now the surface of the recording media is impinged by exciting electrons or photons, the equilibrium conditions no longer prevail where the electron or photon beam strikes. Hence, atoms from the vapor begin to deposit at points of the substrate surface impinged by the electron or photon beam. It is also possible to utilize two different vapor materials so that molecules from the two sources impinge upon the surface of the recording medium with no condensation taking place until impingement of the electron of photon beam. The result is a condensation comprising a compound of the two materials of the vapor beams. In general, upon impingement of the photons or electrons onto a surface where the two vapor beams are impinging, a rapid reaction occurs resulting in the formation of astable compound on the surface. Any volatile compounds which may be formed may be pumped off or condensed away. Thus, for example, it is possible to evaporate zinc or cadmium simultaneously with selenium and direct the vapors toward the recording medium. The resulting condensation will be either zinc selenide or cadmium selenide as soon as the sensitizing beam scans the surface of the recording medium.

RECORDING MEDIA OR SUBSTRATE AND MATERIALS The recording media or substrates mentioned hereinbefore refers to the active recording media of the invention rather than any supporting structure, substrate or carrier therefor whose role is purely passive as far as the practice of the invention is concerned. As used herein, the term recording medium" is intended to include at least a film-forming vehicle and the appropriate materials according to the invention dispersed therein. Where it is not desired or necessary that the active recording film, tape or media be self-supporting, a passive carrier or substrate may be conveniently employed and such a support substrate may be encompassed within the term recording medium." It will thus be understood that the novel recording materials of the invention may be provided in at least two embodiments. In one, the recording materials may be incorporated in a film-forming vehicle or binder which may be processed to provide a self-supporting film. This includes a film which contains reinforcing fibers, of the nature of paperstock fibers and the like. In another embodiment, the recording materials likewise incorporated or dispersed in a film-forming vehicle may be coated upon a support substrate.

Suitable support substrates for use in the latter of these embodiments may be formed of almost any material and may partake of almost any geometry. Thus paper, especially in the form of tape, may serve as a suitable support substrate and is particularly desirable for recording information and the like. Glass may also be used, as well as various types of transparent plastics, such as acetate films and the like (i.e., methyl methacrylate, cellulose acetate). Where the desired deposition is to serve some functional purpose, such as to form the conductive paths for printed circuit boards, resin or plastic support substrates may be employed. Articles of metal may also be utilized as support substrates and provided with a pattern deposition thereon according to the invention.

For recording media of lesser sensitivity, it does appear to be necessary to provide an electrically conductive member or backing plate for the recording medium during the recording process with electrons or ions. Such a backing member may be provided in several ways. It may simply be the table or platform on which the recording medium is disposed during recording. This is particularly true and advantageous where the recording medium is a self-supporting film. In cases where a support substrate is utilized and such support substrate is electrically conductive, it serves as the backing member.

Where the support substrate is electrically non-conductive or an insulator, such as glass or paper, the backing member may be made an integral part of the recording medium and substrate. Thus, in the case of a paper tape, the surface of the tape on which the recording medium is to be disposed may be provided with a thin layer of metal, such as aluminum, for example. Such an aluminized surface maybe obscured or rendered invisible by the film-forming vehicle in which the materials of the invention are dispersed.

In general, the recording materials of the invention comprising a mixture of a material sensitive to the impingement of electrons, ions or photons and a metallic compound or nucleation-inducing agent are dispersed in a film-forming resin or binder. Because of its quantitative predominance, which usually determines the color of the recording media, the material which is sensitive to electrons, ions or photons is sometimes referred to as a pigment. The term sensitive material will be used in this specification as a convenient expression to mean a material which is sensitive to impingement of electrons, ions or photons. The sensitive material and the nucleation-inducing agent are mixed together with an appropriate binder and solvent therefor in an orbital ball mill, for example, after which the mixture is coated upon a desired substrate or formed into a self-supporting film.

A satisfactory binder or matrix for the materials of the invention may be any of many well-known film-forming resins and particularly those of the butadiene and/or styrene type. A typical binder of the styrene-butadiene type which has been used successfully in the practice of the present invention is one identified as Pliolite by the manufacturer thereof, Goodyear Tire and Rubber Co., Chemical Division, Akron, Ohio. Other satisfactory matrix materials are polystyrene, chlorinated rubber, polyvinylidene chloride, polyvinyl butyral and the like. Any suitable solvent for thinning the film-forming resin or otherwise adjusting its miscibility and spreadability may be employed and a typically satisfactory solvent is toluene. It will be understood that neither the binder nor the solvent therefor are of critical importance since the primary purpose is to permit the sensitive material and the nucleationinducing agent materials to be thoroughly mixed and then while still flowable to be supplied to a suitable substrate on which the binder may harden and form a relatively tough film in which the sensitive material and the nucleation-inducing materials are uniformly dispersed. Thus, the binder and the solvent function primarily in a physical manner to provide a support carrier or matrix for the sensitive material and the nucleation-enhancing materials.

The sensitive materials suitable for use in the practice of the present invention appear to include materials which are classifiable as either photo-conductive or photo-emissive or both. As noted hereinbefore, they function for the purposes of the present invention in response to either photons, electrons or ions. In general, the preferred sensitive materials for use in recording media according to the invention include compounds formed by elements of Group II of the Periodic Chart of the Elements (hereinafter referred to as Group II elements) with elements of Group VI thereof (hereinafter referred to as Group VI elements). However, the sensitive materials for use in the recording media of the inventioninclude compounds such as the oxides of titanium, tantalum, indium, magnesium, germanium, iron, tin, and bismuth, as well as sulfides of calcium, zinc, cadmium, and indium. In addition to these, it has been found that such compounds as boron nitride, calcium tungstate, berylliumaluminide, lithium carbonate, zinc carbonate, cadmium niobate, lithium niobate, and certain phosphor compounds, as calcium-magnesium silicate (cesium-activated) may also be employed. Mixtures of these compounds may also be used. In general, the compounds are formed of one element to the left of Group IV compounded with another element from the group the same distance to the right of Group IV. Thus, the compound is balanced about Group IV.

In formulating the recording materials and media of the invention, the amount of the nucleation-inducing material incorporated in the film-forming vehicle is not critical. Ratios of nucleation-inducing agent to sensitive material of from 10 to 10 have given excellent and substantially equivalent results with no discernible differences. Recording media with no nucleation-inducing materials have been found to exhibit no gain or improvement in selective deposition of atoms or molecules.

The nucleation-inducing materials suitable for use in the practice of the present invention are, especially with zinc oxide, any of the metallic or metallo-organic compounds such as metallic halides and metallic acetylacetonates, and particularly the copper halides, copper (II) acetylacetonate, bismuth trioxide (Bi o cuprous chloride, a mixture of cuprous chloride and triethylamine salt of tetra cyanoquinomethane, cuprous chloride and copper (II) acetylacetonate, a mixture of copper formate and cuprous chloride, cupric sulfate, cupric chloride hydrated with two water molecules, cupric bromide, cuprous sulfite, cupric thiocyanate, cuprous sulfide, cupric molybdate, cupric lactate, cupric formate, copper p-toluene sulfinite, cupric salicylate, cupric linoleate, cupric acetate, glycine cupric salt, cupric stearate, cupric oleate, cupric tartrate, cupric citrate, dl malic acid copper salt, cupric oxalate, bis (ethyl acetoacetate) copper, bis (I-phenyl 1,3-Butanedione) copper, cupric dimethyl dithiocarbamate, cuprous sulfate B napthol, cuprous acetyacetonate, silver benzotriazole, silver nitrate, silver oxide and tri-phenylene.

The sensitive material and nucleation-inducing materials in comminuted form are mixed together with the desired binder and solvents in an orbital ball mill until thorough dispersion of the dry ingredients is achieved.

The normal solvent for pliolite 8-7, which is the film-forming binder principally used in the examples hereinafter, is toluene. Sufficient toluene is added to provide proper fluidity.

The toluene thus serves as the principal or primary solvent, providing the necessary fluidity for proper mixing. It was unexpectedly discovered that the employment of a second solvent of proper nature improved the sensitivity. For example, when methanol is employed as a second solvent in the amount of 4-8 milliliters per 100 grams of sensitive material, the nucleation-inducing material is apparently better dispersed in or coated on the sensitive material to provide for greater sensitivity. The greater sensitivity provides a fully created latent image with the impingement of a lesser amount of exposure energy. Thus, the medium of Example No. 38, below, is more sensitive than the medium of Example No. 31. The second solvent is a liquid alcohol having a chain length from 1 to 8, and is preferably methanol. The semi-fluid or viscous mixture is then applied to'a suitable substrate by conventional knifecoating equipment so as to form a film thereon having a wet thickness of about 100 microns, for example. In general, the dry thickness of the film varies between 25 percent to 50 percent of the wet" thickness of the film. Upon drying, the film is ready for use.

The media is thus prepared by dispersing together the appropriate ingredients and coating the mixture upon a suitable substrate. The dispersing step comprises providing a sufficient amount of solvent suitable to solvate the binder to provide fluidity, not only to the binder, but to the entire mixture so that complete dispersion is obtained. However, in addition to the principal, or first solvent, in some cases an additional solvent is employed. This additional solvent is generally an alcohol and is used for two reasons. The use of this second solvent unexpectedly suppresses the background upon development. It also improves the dispersion or solvation of the respective mixtures. The process includes forming a film from the mixture, inmost cases, by coating the solvent including mixture onto a substrate, followed by solvent removal. In view of the fact that the finished surface of the medium must be as smooth as possible to prevent mechanically produced nucleation centers, which would provide spurious images, the top surface must be as level as possible in the finished media. Suf ficient solvent to provide a moderate amount of self-leveling after knife coating aids in eliminating undue surface irregularities. After solvent removal, which may be speeded up by infrared'heating or moderate vacuum application, and following the drying step, the media is ready for use. I

The actual mode of operation, or the manner in which the sensitive material combined with the nucleation-inducing agent operates to increase the overall gain in the nucleation process is not fully understood. However, there is some understanding about the mechanism of operation which might aid in the understanding of the high gain obtained. In describing the bulk amplification, zinc oxide is used as an example of the sensitive material and is the preferred sensitive material, while an organic copper salt, particularly cuprous chloride, is employed as an example of the nucleation-inducing material. When these materials are mixed together for thorough dispersion in a binder, the copper salt appears to coat itself upon at least some of the zinc oxide particles. The zinc oxide particles are preferably in the order of 0.3 microns in diameter or less. If one assumes thatthe zinc oxide surface is covered with a thin film of cuprous chloride, energetic electrons will penetrate this film, upon exposure, and being absorbed within the zinc oxide, generate a large number of actinic photons. These photons may dissociate the cuprous chloride, as follows:

Cu Cl hv 'Cu+CuCl resulting in copper nucleation centers. However, this might not describe properly the high gain obtained in the present invention because a thin cuprous chloride film deposited upon a zinc oxide-pliolite surface does not show the same effect. In fact, the direct impingement of electrons upon a thin-cuprous chloride film itself has about the same sensitivity. Perhaps a more complicated process may take part and one could consider the following:

2110 +.electrons (a) Zn* A 0, Zn Cu Cl- Zn Cl, +'2Cu* n(2Cu*) electrons (b) Cu stable cluster *Excited state a. Electrons from recording electron beam (1 KV to about b. Free electrons resulting from electron-hole-pair generation in adjacent zinc oxide crystals, which are, subsequently trapped at the point of beam incidence. The holes are assumed to be trapped near the point of pair generation.

The following examples are intended to illustrate the preparation of the novel recording media of the invention and not to restrict the scope thereof. The examples identify the nucleation-inducing compound of this specification as sensitizer, for brevity. Examples 83 through 87 show the sensitivity of those media by showing the amount of electron beam exposure in electrons per square centimeter necessary to produce a fully exposed image, leaving a differential density of 0.3 above the fog level.

EXAMPLE NO.1

A recording tape according to the invention was prepared by adding 35 grams of ZnO, as pigment; 0.018 gram of CuCl, as nucleation-inducing compound; 9 grams of 30 percent solids in toluene solution of Pliolite S-7; and 50 ml of toluene together in an orbital ball mill. (Pliolite 8-7 is a resinous copolymer of butadiene and styrene manufactured and sold under that designation by Goodyear Tire and'Rubber Co., of Akron, Ohio.) The materials were milled together for 1.5 hours, usin g grams of glass balls. The ratio of ZnO to dry binder was 13 to l. The ratio of NIC to pigment was 0.00046 to l. Thereafter, a film of the composition was applied bya knife-coater at a speed of 2 cm. per second on the aluminized surface of a paper tape. Tapes were prepared'having various film thicknesses (in microns), as follows:

Wet

Latent images, or nucleation sites, were subsequently formed and developed on these tapes. The'developed images were found to be sharp with good continuous tone qualities. The resolving power exceeded 256 line pairs per mm.

Additional examples of tape formulations and compositions are given below. Where ZnO is listed as the pigment, it was New Jersey Zinc Co. Photox 801 zinc oxide, unlessotherwise indicated. In each of these recording tape compositions, a solvent was employed. Sufficient solvent was employed to permit complete dispersion in the ball milling operation and to make the composition sufficiently fluid for proper coating. The solvent was toluene, except where otherwise specified.

Ball milling was accomplished, as indicated in Example I, for a sufficient length of time to provide proper dispersion of all components of the composition.

After ball milling, the composition was coated onto the substrate by means of standard coating apparatus. Wet coating thickness was in the order of 100 microns, to result in a dry coating thickness of 25 to 50 microns, depending upon the amount of solids in the tape composition, as coated. The substrate was aluminized paper tape, with the coating being applied to the aluminized side.

Where an additive was indicated as being employed in the composition, the amount of the additive was in the range of 4 to 8 milliliters per hundred grams of pigment.

Each of the tape compositions was recorded upon by forming latent images, followed by development. The developed images were found to be sharp, with good continuous tone qualities. The amount of sensitivity, or the amount of exposure energy employable to obtain a fully developable image varied with the several tape compositions. However, each was sufficiently sensitive to have utility. It was found that the overall sensitivity was directly related to the photon or electron sensitivity of the pigments.

Sensitizer/Pigment EXAMPLE NO. 3

Pigment: Binder:

ratio:

Pigment/dry binder ratio:

Sensitizer: Sensitizer/Pigment EXAMPLE NO. 4

Pigment: Binder:

ratio:

Pigment/dry binder ratio:

Sensitizer: Sensitizer/Pigment EXAMPLE NO. 5

Pigment: Binder:

ratio:

Pigment/dry binder ratio:

Sensitizer: Sensitizer/ Pigment EXAMPLE NO. 6

Pigment: Binder:

Ratio:

Pigment/dry binder ratio:

Sensitizer: Sensitizer/Pigment EXAMPLE NO. 7

Pigment:

ZnO to CdS Ratio: Binder:

Total Pigment/dry Sensitizer:

Ratio:

binder ratio:

Sensitizer/total Pigment ratio:

EXAMPLE NO. 8

Pigment: Binder:

Pigment/dry binder ratio:

Sensitizer: Sensitizer/Pigment EXAMPLE NO. 9

Pigment: Binder:

ratio:

Pigment/dry binder ratio:

Sensitizer: Sensitizer/ Pigment EXAMPLE NO. 10

Pigment: Binder:

ratio:

Pigment/dry binder ratio:

Sensitizer: Sensitizer/Pigment EXAMPLE NO. 1 l

Pigment: Binder:

ratio:

Pigment/dry binder ratio:

Sensitizer: Sensitizer/Pigment EXAMPLE NO. l2

Pigment: Binder:

ratio:

Pigment/dry binder ratio:

Sensitizer: Sensitizer/Pigment EXAMPLE NO. 13

Pigment: Binder:

ratio:

TiO

Pliolite S7 CuCl 5 0.00046} l 2 5 Pliolite S-7 72/ l CuCl 0.00028/ 1 MgO Pliolite S-7 6.7/ i CuCl CdS Pliolite S-7 22. 5/ l CuCl 0.00089 ZnO and CdS .5 8/24 Pliolite 8-7 152/] CuCl 0.0013/] Ca-Mg( SiO zce Pliolite 8-7 CuCl CaWO. Pliolite S-7 1 3.4/ i CuCl ZnS Pliolite S-7 CuCl CaS Pliolite S-7 1 3.4/ l CuCl SnO Pliolite s-v Pigment/dry binder ratio:

Sensitizer:

Sensitizer/Pigment ratio:

EXAMPLE NO.

Pigment:

Binder:

Pigment/dry binder ratio:

Sensitizer:

Sensitizer/Pigment ratio:

EXAMPLE NO.

Pigment:

Binder:

Pigment/dry binder ratio Sensitizer:

Sensitizer/Pigment ratio:

EXAMPLE NO.

Pigment:

Binder:

Pigment/dry binder ratio:

Sensitizer:

Sensitizer/Pigment ratio:

EXAMPLE NO.

Pigment:

Binder:

Pigment/dry binder ratio:

Sensitizer:

Sensitizer/Pigment ratio:

EXAMPLE NO.

Pigment:

Binder:

Pigment/dry binder ratio:

Sensitizer:

Sensitizer/Pigment ratio:

EXAMPLE NO.

Pigment:

Binder:

Pigment/dry binder ratio:

Sensitizer:

Sensitizer/Pigment ratio:

EXAMPLE NO.

Pigment:

Binder:

Pigment/dry binder ratio:

Sensitizer:

Sensitizer/Pigment ratio:

EXAMPLE NO.

Pigment:

Binder:

Pigment/dry binder ratio:

Sensitizer:

Sensitizer/Pigment ratio:

EXAMPLE NO.

Pigment:

Binder:

Pigment/dry binder ratio:

Sensitizer:

Sensitizer/Pigment ratio:

EXAMPLE NO.

Pigment:

Binder:

Pigment/dry binder ratio:

Sensitizer:

SnCL to CuCl ratio: Total sensitizer/Pigment ratio:

EXAMPLE NO.

Pigment: Binder: Pigment/dry binder ratio: Sensitizer:

Sensitizer/Pigment ratio:

13.4/1 CuCl 0.00] 5/i 3 2'( o m) Pliolite S-7 CuCl Li,CO Pliolite S-7 13.4/ i

CuCl

131 0 Pliolite S-7 -l 3.4/] CuCl ZnS Pliolite S-7 CuCl 0.00 l 5/] ZnCO; Pliolite S-7 1 3.4/ i

CdNb O Pliolite S-7 6/ l CuCl 0.0025 l LiNb O Pliolite s4 1 3.4 1 CuCl Pliolite S-7 8.8/1

CuCl

0.00 l S/l ZnO Pliolite S-7 SnCl and CuCl 2.5/1

ZnO Pliolite 8-7 I 13/] EXAMPLENO. 25

Pigment: Binder: Pigment/dry binder, ratio: Sensitiz er:

Sensitizer/Pigment ratio:

EXAMPLE'NO. 26

Pigment:

Binder:

Pigment/dry binder. ratio: Sensitizer: Sensitizer/Pigment ratio:

EXAMPLE NO. 27

Pigment:

Binder:

Pigment/dry binder. ratio: Sensitizer: Sensitizer/Pigment ratio:

EXAMPLE NO. 28

Pigment:

Binder:

Pigment/dry binder ratio:

Sensitizer: Sensitizer/Pigment ratio:

EXAMPLE NO. 29

Pigment: Binder: Pigment/dry binder ratio: Sensitizer: Sensitizer/Pigment ratio:

Additive:

' EXAMPLE NO. 30

Pigment: Binder: Pigment/dry binder ratio: Sensitizer:

Sensitizer/Pigment ratio:

EXAMPLE'NO. '31

' 'zno Pigment:

Binder: Pigment/drybinder ratio: Sensitizer: Sensitizer/Pigment ratio:

EXAMPLE NO. 32

Sensitizer/Pigment ratio:

EXAMPLENO. 35

Pigment:

'Binder: Pigment/dry binder ratio:

ZnO Pliolite 8-7 I 13/ l Ct Br 0.0054 v ZnO Pliolite 8-7 1 3/1 ZnO Pliolite 'S-7 1 3 .4/ l

Pliolite S- 7 ZnO Pliolite s-7 MP 0.002/1 Methanol ZnO Pliolite s-7 16.7] I CuCl Pliolite -7 8.5/ l

CuCl 0.0023/l M20 Pliolite S-7 I 2/ l 'CuCl No.00 /1 Pliolite s7 9.4 1

Copper (11) Acetylacetonatea 1 :)z I

Additive:

Sensitizer:

Sensitizer/Pigment ratio:

EXAMPLE NO. 36

Pigment: Binder: :Pigment/drybinder ratio: Sensitizer:

Sens itizer ratio: Total Sensitizer/Pigmentratio:

EXAMPLENO. 37

Pigment:

Binder:

Pigment/dry binder ratio: Sensitizer:

Sensitizer/Pigment ratio:

Zinc (11) Acetylacetonate- 'Zn(C,H BE2),

ZnO

Pliolite 8-7 9.4/1 Chromium (lll) Acetylacetonate- 1 03 0.00 1 1 EXAMPLE NO. 38

Pigment:

Binder: Pigment/dry binder ratio: Sensitizer: Sensitizer/Pigment ratio:

: EXAMPLE NO. 39

Pigment:

Binder:

Pigment/dry binder ratio:

Sensitizer:

CuCl/Pigment ratio:

TCNQ/Pigment ratio:

Additive:

EXAMPLE NO. 40

' Pigment:

Binder:

Pigment/dry binder ratio:

Sen sitizer:

dioxane-CJLO;

ZnO PlioliteS-7 9.4/ l Nickel (ll) Acetylacetonate- ZnO Pliolite 8-7 9.4/1

CuCl/Pigment ratio: C a 1 zh/Pigment ratio:

Additive:

EXAMPLE NO. 4l

Pigment: Binder: 7 Pigment/dry binder ratio: Sensitizer:

Copper formate/Pigment ratio: CuCl/Pigment ratio: Additive:

EXAMPLE NO. 42

Pigment:

Binder: Pigment/dry'binder ratio: Sensitizer: Sensitizer/Pigment ratio: Additive:

. EXAMPLE NO. 43

Pigment:

Binder:

Pigment/dry binderratio: Sensitizer: Sensitizer/Pigment ratio: Additive:

EXAMPLE NO. 44

Pigment: I

Binder: Pigment/dry binder ratio:

ZnO Pliolite S-7 10/ 1 CuCl 0.002/1 Methanol ZnO Pliolite S-7 CuCl and triethylamine salt of tetra cyanoquinomethane (TCNQ) Methanol ZnO Pliolite 5-7 9.3/ l

CuCl and s 1 2)2 0.005/ 1 Methanol ZnO Pliolite S-7 9.3/1

Copper formate .and CuCl 0.003/1 0.002/1 Methanol ZnO Pliolite S-7 14/ l Cupric sulfate 0.001 3/ l Methanol ZnO Pliolite 5-7 9.3/ l CuCl,'2H,O 0.002/1 Methanol ZnO Pliolite S-7 1 4/ l Sensitizer: Sensitizer/Pigment ratio: Additive:

EXAMPLE NO. 45

Pigment: Binder: Pigment/dry binder ratio: Sensitizer: Sensitizer/ Pigment ratio: Additive:

EXAMPLE NO. 46

Pigment: Binder: Pigment/dry binder ratio: Sensitizer: Sensitizer/Pigment ratio: Additive:

EXAMPLE NO. 47

Pigment: Binder: Pigment/dry binder ratio: Sensitizer: Sensitizer/Pigment ratio: Additive:

EXAMPLE NO. 48

Pigment: Binder: Pigment/dry binder ratio: Sensitizer: Sensitizer/Pigment ratio: Additive:

EXAMPLE NO. 49

Pigment: I Binder: Pigment/dry binder ratio: Sensitizer: Sensitizer/Pigment ratio: Additive:

EXAMPLE NO. 50

Pigment: Binder: Pigment/dry binder ratio: Sensitizer: Sensitizer/Pigment ratio: Additive:

EXAMPLE NO. 51

Pigment: Binder: Pigment/dry binder ratio: Sensitizer:

Sensitizer/Pigment ratio:

Additive:

EXAMPLE NO. 52

Pigment: Binder: Pigment/dry binder ratio: Sensitizer: Sensitizer/Pigment ratio: Additive:

EXAMPLE NO. 53

Pigment: Binder: Pigment/dry binder ratio: Sensitizer: Sensitizer/Pigment ratio: Additive:

EXAMPLE NO. 54

Pigment: Binder: Pigment/dry binder ratio: Sensitizer:

Sensitizer/Pigment ratio:

Cupric bromide 0.001 3/ 1 Methanol ZnO Pliolite S-7 14/ 1 Cuprous sulfite 0.00 l 3/ l Methanol ZnO Pliolite S-7 Cupric thiocyanate 0.001 3/ 1 Methanol ZnO- Pliolite S-7 14/1 Cuprous sulfide 0.001 3/ l Methanol ZnO Pliolite S-7 Cupric molybdate 0.001 3/ 1 Methanol ZnO Pliolite S-7 14/ l Cupric lactate 0.001 3/ 1 Methanol ZnO Pliolite 8-7 9.3/ 1

Copper formate 0.003/ 1 Methanol ZnO Pliolite S7 Copper p-toluene sulfinite 0.00 l 7/ l Methanol ZnO Pliolite S-7 Cupric salicylate 0.00 l 3/ l Methanol ZnO Pliolite S-7 Cupric linolcate 0.00 l 3/ 1 Methanol ZnO Pliolite S-7 14/1 Cupric acetate 0.00 1 3/ l Additive:

EXAMPLE NO. 55

Pigment: Binder: Pigment/dry binder ratio: Sensitizer:

Sensitizer/Pigment ratio:

Additive:

EXAMPLE NO. 56

Pigment: Binder: Pigment/dry binder ratio: Sensitizer: Sensitizer/Pigment ratio: Additive:

EXAMPLE NO. 57

Pigment: Binder: Pigment/dry binder ratio: Sensitizer: Sensitizer/Pigment ratio: Additive:

EXAMPLE NO. 5 8

Pigment: Binder: Pigment/dry binder ratio: Sensitizer: Sensitizer/Pigment ratio: Additive:

EXAMPLE NO. 59

Pigment: Binder: Pigment/dry binder ratio: Sensitizer: Sensitizer/Pigment ratio: Additive:

EXAMPLE NO. 60

Pigment: Binder: Pigment/dry binder ratio: Sensitizer:

Sensitizer/Pigment ratio: Additive:

EXAMPLE NO. 61

Pigment: Binder: Pigment/dry binder ratio: Sensitizer:- Sensitizer/Pigment ratio: Additive:

EXAMPLE NO. 62

Pigment: Binder: Pigment/dry binder ratio: Sensitizer:

Sensitizer/Pigment ratio: Additive:

EXAMPLE NO. 63

Pigment: Binder: Pigment/dry binder ratio: Sensitizer:

Sensitizer/Pigment ratio: Additive:

EXAMPLE NO. 64

Pigment: Binder:

Pigment/dry binder ratio:

Methanol ZnO Pliolite S-7 14/ l Glycine cupric salt 0.001 3/ l Methanol ZnO Pliolite S-7 Cupric stearate 0.0013/1 Methanol ZnO Pliolite S-7 14/ l Cupric oleate 0.00 l 3/ l Methanol ZnO Pliolite S-7 14/ l Cupric tartrate 0.00 1 3/ l Methanol ZnO Pliolite S-7 14/ 1 Cupric citrate 0.001 3/ 1 Methanol ZnO Pliolite S-7 14/ 1 dl malic acid copper salt 0.0013/1 Methanol ZnO Pliolite S--7 14/1 Cupric oxalate 0.0013/1 Methanol ZnO Pliolite S-7 Bis (ethyl acetoacetate) copper 0.0024/ 1 Methanol Pliolite S-7 Bis l-phenyl 1,3-

Butane-dione) copper Methanol ZnO Pliolite S-7 14/ l Additive:

Cuprjodim ethyl-z dithiocarbamate 0.0013] 1 1 Methanol. I

PhthOl 0.001 3/1 Methanol,

1 cuprous acetyoaeetonate t 0.0032/1 Methanol ZnO Pliolite 5-1 14/ l 0.0013/1 Methanol ZnO 1 Pliolite 8-7 0.00 l 3/ l v Methanol ZnOg. Pliolite S:7 14/1;

AgO.

0.00 l 3/1- Methanol,

Pliolite S 7 l4/l, Tri phenylene 0.00.l3/l Methanol ZnONJZinc Co.

(t.c. l689) Pliolite 5-7 Cupric lactate Methanol- ZnO NJ ZincCo. (C0-026-6) Pliolite 8-7 Cupric lactate Methanol- -Co., Ard sley,

PlioliteS-J 1'4/ 1 Cupric lactate 0.00] 3/ l Methanol Sensitizer:

Sensitizer/Pigment ratio; Additive:

EXAMPLE NO. 65

Pigment: Binder: Pigment/dry binderratio: Sensitizer:v

Sensitizer/Pigmmt :ratioz, Additive:

' EXAMPLE N0. 6 Pigment: I I 1 Binder: Pigment/dry binderratio:

Sensitizer:

Sensitizer/Pigment ratio Additive:

EX AMP I'.E1 IO.- 67' Pigment: Binder: Pigment/dry binder ratio: Sensitizer: Sensitizer/Pigment ratio: Additive:

' EXAMPLE Notes Pigment: Binder: Pigment/dry binderratio: Sensitizer: Sensitizer/Pjgment ratio: Additive:

EXAMPLE-N0469- Pigment:- Binder: I Pigment/dry. binder. ratio: Sensitizer: Sensitizer/Pigment ratio: Additive:

EXAMPLE. N0. 70 Pigment: Binder: Pigment/dry binder-ratio: Sensitizer: Sensitizer/Pigment ratio: Additive:

EXAMPLE, NQ; 7i;

Pigment:

Binder: Pigment/dry binderratioz. Sensitizer: Sensitizer/Pigmentratio:, Additive:

EXAMPLE-NO: 72

Pigment:

Binder: Pigment/dry binder ratio:

Sensitiz er: Sensitizer/Pigment ratio:v Additive:

EXAMBEE; No. 73

Pigment:

Binder: Pigment/dry binder. ratio: Sensitizer: Sensitizer/Pigmentratio:

l 8'; EXAMPLE 7 4 Pigment: Binder: Pigmentldry binder ratio: Sensitiz er: Sensitizer/Pigment ratio: Additive:

EXAMPLE NO. 75

Pigments: I I

Binder; Pigment/dry binder ratio: Sensitizer: Sensitizer/Pigment ratio: Additive:

EXAMPLE NO.;76

Pigment:

nde Pigment/dry binderratio: Sensitizer: Sensitizer/Pigrnent ratio: Additive:

EXAMPLENO. 77

Pigment:

Binder: Pigment/dry binder ratio: Sens itizerz, Sensitizer/ Pigment ratio: Additive;

EXAMPLE-No.78

itt an Binder: Pigment/dry binder ratio: Sensitizer; Sensitizer/Pigment ratio: Additive:

NO. 79 Pigment:

Binder; Pigment/dry binder ratio: Sensitjzer: Sensitizer/Pigmentratio: Additive:

EXAMPLE NO. 80 men Binder:

tm d y b nderatio Sensitizer: Sensit er/Pigment 'ratio: dd t EXAMPLE 81 Pigment: Binder;

Pigment/dry binderratio: Sensitiaer:

SensitizerlPigrnent ratioz Additive:

Pigment:

EXAMPLE No. 82

a e. Pliolite S.-7- l4/ 1 Cupric, lactate 0.001 3/ l Methanol 50% ZnO 50% Fe,0, Pliolite, 5-7 14/ l Cupric lactate 0.001 3/ l Methanol ZnO plua 1.3% Fluorescent po h nne Luminous Materials Co., L.A.

Superfine Pigment.

No. 8639) Iv Pliol ite 54 14/1} Cupric lactate 0.0013! 1 I tha ol ZnO (NJZ inc Cov Kadox 72) Pliolite .S-7

Cupric lactate Methanol Pliolite S,7

Cupric lactate Methanol ZnO-NJ Zinc. Co.

5-09 (De-Soto Resin, lnc.) a modified l yd Cupric lactate Methanol ZnO E-09 (DeSoto Resin,lnc.)

Cupric lactate Methanol ZnO Binder: E028( DeSoto Resin,lnc.)

Pigment/dry binder ratio: 14/ l 1 Sensitizer: Cupric lactate Sensitizer/Pigment ratio: 0.00l3/ l Additive: Methanol i 5 EXAMPLE NO. 83

Pigment: ZnO Binder: Pliolite S-7 plus 33% Tenlo 70, a modified polyamine dispersing agent, Chemical Additives Co., L.A. Pigment/dry binder ratio: l4/l Sensitizer: Cupric lactate Sensitizer/Pigment ratio: 0.0013/1 Additive: Methanol Exposure: 2X10 inches EXAMPLE NO. 84

Pigment: ZnO Binder: Pliolite S-7 Pigment/dry binder ratio: 14/ l Sensitizer: Cupric lactate Sensitizer/Pigment ratio: 0.0013 Additive: Methanol Exposure: 9 l0 EXAMPLE NO. 85

Pigment: ZnO Binder: Pliolite S-7 Pigment/dry binder ratio: 5.0/1 Sensitizer: Cupric lactate plus 7 0.10% Tenlo 70 'Sensitizer/Pigment ratio: 0.00] 3/l Additive: Methanol Exposure: 5 l0 EXAMPLE NO. 86

Pigment: ZnO Binder: Pliolite S-7 Pigment/dry binder ratio: l4/ 1 4o Sensitizerz Cuprous acetylacetonate Sensitizer/Pigment ratio: 0.00 l 2/ l Additive: Methanol Exposure: 5.5 l0

' EXAMPLE NO. 87

Pigment: ZnO Binder: Pliolite S-7 Pigment/dry binder ratio: l4/l Sensitizer: Cupricchloride Sensitizer/Pigrnent ratio: 0.0005/1 Additive: Methanol Exposure: l l0 DEVELOPER MATERIALS AND DEVELOPMENT To render the latent images visible or otherwise useful, the recording medium is exposed in vacuo to the vapor of a material which selectively grows only on and from the sensitized or nucleated areas thereof. Generally, the developer materials are metals, such as magnesium, zinc, cadmium or 0 mercury. The latter of these metals, namely mercury, may, under some circumstances, be less desirable than the other metals listed for this purpose, although under suitable temperature conditions, mercury may be useful and can produce images of relative permanence and with other desirable characteristics. As suggested in FIG. 1, development can be performed in the same evacuated chamber in which the latent images are formed. Alternatively, a separate developing chamber may be utilized. I

Development or formation of a visible image takes place under the usual and known conditions governing the deposition of metals in vacuo. Thus, the development step can be performed in conventional deposition or coating apparatus, comprising a vacuum chamberin which a boat or wire source (i.e., nickel, Nichrome, or other material) is used to vaporize the development metal. The recording media to be developed may be located at a distance from the vapor-producing source which does not unduly exceed the mean free path existing in the chamber at given conditions. Pressures in the range of about l0- to 10 mmfof mercury may be used for this purpose. Helium-argon or argon-hydrogen mixtures may also be employed and introduced into the chamber to modify the velocity at which the vapor molecules reach the surface of the recording medium, permitting a greater degree in controlling the contrast of the image being developed. It is also possible, instead of directly vaporizing a metal, to employ ametal compound which may controllably be caused to undergo decomposition on the nucleation sites and result in the deposition of metal thereat. To achieve this result, the recording medium must be maintained at the proper temperature, generally corresponding to the decomposition temperature of the compound. Nickel carbonyl is a typical example for vapor-plating from a metal compound.

According to the invention, both continuous and half-tone images may be produced. When the recording medium and/or any supporting substrate is transparent, the image formed can be diapositive or dianegative and the resulting record is useful for. optical projection. Also, as noted previously, the metallic images may have important uses other than as simple visible records. Such other uses lie in the fields of microcircuitry,

.computer storage modules, printed circuits and the like.

Referring now to FIG. 4, a continuous process of sensitization or recording and utilization is demonstrated in the apparatus schematically shown. A continuous supply of tape 12 is maintained by means of the supply reel 14 which is disposed in a light-tight box 16. This may comprise a metallized paper or Mylar tape which is coated with any of the recording compositions described previously in the examples The first operation is that of forming a latent image on the tape which operation is achieved in a light-tight box 18 which is also evacuated. Disposed with the evacuated box 18 are means 20 for forming a scanning electron beam or ion beam, for example. The electron or ion beam is adapted to be controlled (scanned and/or modulated) across the surface of the tape 12 in accordance with electrical signals which may represent radar or video information from a signal source 22. The beam may also be controlled in accordance with electrical signals derived from a computer or other program means for producing electrical signals so as to form a latent image on the surface of the tape corresponding to any pattern desired to be formed. lnasmuch as the recording media of the invention are photo-sensitive, the tape is fed from the supply box 16 to the recording box 18 without exposure to light, the means for permitting such transfer being slit 24 between the boxes.

After the desired latent image is formed on the 'tape 12 in the recording box 18, the tape continues its travel through 'slit 5 chamber 28 will also be light-tight and evacuated in the manner set forth hereinbefore.

After the desired development is achieved, the tape continues its travel through a reading station, for example, although it will be appreciated that this particular embodiment is not necessarily the only means of utilizing the tape. Thus, the reading station could be replaced by any other type of apparatus in order to either perform other operations on the tape or to utilize it in some other manner. For example, the reading station could comprise a continuous dip-soldering operation in which printed circuit patterns are beefed" up with a solder overlay, as is conventional in printed circuit techniques. In the embodiment shown, it is contemplated that the images recorded represent information which it is desired to immediately read and retain. It may be desirable that the tape 12 be a transparency so that light from a source 32 may be projected therethrough and focused by means of a lens 34 onto a screen 36 for viewing and reading. Thereafter, the tape is taken up and stored on a storage reel 38 in a storage chamber 40. Inasmuch as the entire operation of recording and developing may be carried on in near reel time, it will be appreciated by this apparatus that it is possible to almost instantaneously record and read incoming information, e.g., 60 fields or 30 frames per second, as required for conventional video recording/readout.

It is also possible to modify the apparatus shown in FIG. 4 and use the tape 12 merely as a conveyor belt which would carry objects on which a desired image is to be formed. Thus, printed circuit boards can be placed on the conveyor tapeand transported thereby to the various stations for processing so as to have some predetermined indicia or conductive pattern formed thereon.

In FIG. 5, another system is schematically depicted which permits information representative images to. be read electronically. Disposed within a light-tight evacuated chamber 42 is a recording medium 44 according to theinvention. The recording medium 44 is adapted to be scanned by an electron ,or ion beam from a source .46 in accordance with electrical signals from a source 48. These signals may represent radar or video information, for example. As soon as the latent image is formed on the substrate .44, a vapor source, likewise disposed within thechamber 42, is activated to develop the image in accordance with the .process of the invention. Thereafter, by bombarding the developed substrate 44 withelectrons from a scanning beam, source 47 photons are emitted from the substrate 44 in accordance with the image content on the tape. These photons are picked up by a photo detector 52, for example, which translates the optical information into electrical signals which are fedto aconventional cathode ray tube or other display apparatus 54 where the information may be read or viewed. In this manner, not .only is a permanent record made of the incoming information, but it may also be readily viewed and read. On such readout, the fluorescent light output is an order of magnitude higher when the nucleation-inducing compound is an organic salt, as compared to an inorganic salt. Such a system, as shown in FIG. 5, has significant utility in situations where it is desired to read or display information at a location remote from the recording station.

i There, thus have been described methods and means for making prints or records either on discrete novel recording media or on acontinuous tape or even upon discrete objects to which a coating of the novel recording medium of the invention is applied. It will be appreciated that'many modifications of the invention may be made, some of which have been demonstrated, without departing from the scope of the invention. Because of the speed and demonstrated versatility of the novel recording materials of the invention, many uses heretoforeimpossible or impracticahsuch as instantaneous recording or reading, may be realized. The instantspecification has representatively illustrated the range of possible applications of the invention.

In the nucleation recording media of prior art utilizing surface effects only, measurements show that the required exposure in ergs/cm to produce nucleation centers by photons is 10; by electrons, 2 X10; and by ions, 2 X 10 In contrast, the recording media of the present invention produce nucleation centers by photons with an exposure of IO ergs/cm and by electrons .with an exposure of 20 ergslcm The recording media of the invention make possible high speed, high resolution video recordings, for example, with beam currents of less than 10" amperes and writing speeds of better than 100 cm /sec. It has also been found that with the'recording media of the invention, the resolving power capability is more than 256 line pair/mm. Thus, in the case of video recordings and assuming a possible spot size of about'2 microns, 2.5 X 10 bits/sec. may be recorded without even stressing the resolving powercapability of the recording media of the invention. In addition, the inherent properties of the recording media to emit photons in the blue region of the spectrum upon being bombarded with electrons makes feasible a simple lensless retrieval system whereby the developedimage can modulate the photon flux in proportion to its density when scanned by any electron beam of constant energy andfluxdensity.

What is claimed is:

1. In a nucleation-recording medium comprising:

a resinous film-forming vehicle in which is dispersed, with the aid of a first solvent suitable to solvate the resinous film-forming vehicle;

an actinic ray sensitive compound selected from the group consisting of oxides of titanium, tantalum, indium, magnesium, germanium, zinc, iron, tin, and bismuth, sulfides of calcium, zinc, cadmium and indium, and boron nitride, calcium tungstate, beryllium aluminide, lithium carbonate, zinc carbonate, cadmium niobate, lithium niobate, calcium magnesium silicate (cesium-activated) and mixtures thereof; the improvement comprising:

dispersing in said vehicle with the aid of a second-solvent consisting of a liquid lower alcohol having a chain length from 1 to 8, a metallic salt selected from the group consisting. of copper halide, copper (II) acetylacetonate, nickel (II) acetylacetonate, zinc (II) acetylacetonate, chromium (Ill) acetylacetonate, bismuth trioxide (Bi O cuprous chloride, a mixture of cuprous chloride and triethylamine salt of tetra cyanoquinomethane, a mixture of cuprous chloride and copper (II) acetylacetonate, a mixture of copper formate and cuprous chloride, cupric sulfate, cupric chloride hydrated with two water molecules, cuprous bromide, cuprous iodide, cupric bromide, cuprous sulfite, cupric thiocyanate, cuprous sulfide, cupric molybdate, cupric lactate, cupric formate, copper p-toluene sulfinite, cupric salicylate, cupric linoleate, cupric acetate, glycine cupric salt, cupric stearate, cupric oleate, cupric tartrate, cupric citrate, dextro-levo malic acid copper salt, cupric oxalate, bis (ethyl acetoacetate) copper, bis (l-phenyl 1,3-Butane-dione) copper, cupric dimethyl dithiocarbamate, cuprous sulfate B napthol, cuprous acetylacetonate, silver benzotriazole, tin chloride, nickel chloride, chromium chloride, nickel sulfate, nickel fluoride, silver nitrate, and silver oxide which acts as a nucleation-enhancing compound which acts with the sensitive material upon actinic ray impingement-to enhance nucleation so that nucleation sites are formed in accordance with actinic ray exposure.

2. The nucleation-recording medium of said metallic salt is a copper salt.

3.The recording medium of claim 2 wherein said copper salt is'selected from the group consisting of copper halides and claim 1 wherein copper organic salts.

4. The nucleation-recording medium of claim 3 wherein said copper salt is selected from the group consisting of copper salts of lower organic fatty acids, copper lactate and copper acetylacetonate, g

5. The nucleation recording medium of claim 1 wherein said medium is. coated upon an electrically conductive backing member.

' 6. The nucleation recording medium of claim 4 wherein said metallic salt is cupric lactate.

7 A nucleation-recording medium produced by the process including the step of dispersing together:

a resinous film-forming vehicle; a solvent for said vehicle;

an actinic ray sensitive material comprising a compound selected from the group consisting of oxides of titanium, tantalum, indium, magnesium, germanium, zinc, iron, tin and bismuth, sulfides of calcium, zinc, cadmium and indium, and boron nitride, calcium tungstate, beryllium aluminide, lithium carbonate, zinc carbonate, cadmium niobate, lithium niobate, calcium-magnesium silicate (cesium-activated) and mixtures thereof; a nucleation-inducing metallic compound selected from the group consisting of copper halide, copper (ll) acetylacetonate, nickel (ll) acetylacetonate, zinc (ll) acetylacetonate, chromium (III) acetylacetonate, bismuth trioxide (Bi O cuprous chloride, a mixture of cuprous chloride and triethylamine salt of tetra cyanoquinomethane, a mixture of cuprous chloride and copper (ll) acetylacetonate, a mixture of copper formate and cuprous chloride, cupric sulfate, cupric chloride hydrated with two water molecules, cuprous bromide, cuprous iodide, cupric bromide, cuprous sulfite, cupric thiocyanate, cuprous sulfide, cupric molybdate, cupric lactate, cupric formate, copper p-toluene sulfinite, cupric the group consisting of copper halide, copper (ll) acetylacetonate, nickel (ll) acetylacetonate, zinc (ll) acetylacetonate, chromium (III) acetylacetonate, bismuth trioxide Bi o cuprous chloride, a mixture of salicylate, cupric linoleate, cupric acetate, glycine cupric pr Chlori n triethylamine Salt of tetra salt, cupric stearate, cupric oleate, cupric tartrate, cupric y n q i a miXtul'e f cup hl ri and citrate, dextro-levo malic acid copper salt, cupric oxalate, pp yl n a mixture of copper formate bis (ethyl acetoacetate) copper, bis (l-phenyl l,3-Buand cuprous chloride, cupric sulfate, cupric chloride tane-dione) copper, cupric dimethyl dithiocarbamate, l0 hydrated with two water molecules, cuprous bromide,

cuprous sulfate B naphtol, cuprous acetylacetonate, silver benzotriazole, tin chloride, nickel chloride, chromium chloride, nickel sulfate, nickel fluoride, silver nitrate, silver oxide and tri-phenylene; and

cuprous iodide, cupric bromide, cuprous sulfite, cupric thiocyanate, cuprous sulfide, cupric molybdate, cupric lactate, cupric forrnate, copper p-toluene sulfinite, cupric salicylate, cupric linoleate, cupric acetate, glycine cupric salt, cupric stearate, cupric oleate, cupric tartrate, cupric 15 citrate, dextro-levo malic acid copper salt, cupric oxalate,

bis (ethyl acetoacetate) copper, bis (l-phenyl 1,3-Butane-dione) copper, cupric dimethyl dithiocarbamate, cuprous sulfate B naphthol, tin chloride, nickel chloride, chromium chloride, cuprous acetylacetonate, silver benzotriazole, nickel sulfate, nickel fluoride, silver nitrate, silver oxide and tri-phenylene and a liquid alcohol having a chain length from 1 to 8 to reduce background nucleation; forming a film of said dispersion, including evaporation of pound which is sensitive to actinic rays selected from the group consisting of oxides of titanium, tantalum, indium, magnesium, germanium, zinc, iron, tin and bismuth, sulfides of calcium, zinc, cadmium and indium, and boron nitride, calcium tungstate, beryllium aluminide, lithium carbonate, zinc carbonate, cadmium niobate, lithium niobate, calcium-magnesium silicate (cesium-activated) substantially all of both said solvent and said alcohol;

imagewise exposing said film to actinic radiation to form a latent image of nucleation sites in accordance withthe imagewise exposure;

exposing said film to metal vapor under such conditions that metal vapor deposits upon the nucleation sites to form a visible image.

13. The process of producing a nucleation-recording medium with an image thereon comprises the steps of:

dispersing together a resinous film-forming binder, an acand mixtures thereof, a nucleation-enhancing metal salt selected from the group consisting of copper halide,

copper (ll) acetylacetonate, nickel (ll) acetylacetonate,

zinc (II) acetylacetonate, chromium (III) acetylacetonate, bismuth trioxide 1350, cuprous chloride, a mixture of cuprous chloride and triethylamine salt of tetra cyanoquinomethane, a mixture of cuprous chloride and copper (ll) acetylacetonate, a mixture of copper formate and cuprous chloride, cupric sulfate, cupric chloride hydrated with two water molecules, cuprous bromide, cuprous iodide, cupric bromide, cuprous sulfite, cupric thiocyanate, cuprous sulfide,

tinic ray sensitive compound selected from the group consisting of oxides'of titanium, tantalum, indium, magnesium, germanium, zinc, iron, tin and bismuth, sulfides of calcium, zinc, cadmium and indium, and boron nitride, calcium tungstate, beryllium aluminide, lithium carbonate, zinc carbonate, cadmium niobate, lithium niobate, calcium-magnesium silicate (cesium-activated) and mixtures thereof, a solvent for said film-forming binder, a nucleation-inducing metallic salt selected from 5: p-toluene sulfinite, cupric salicylate, cupric linoleate, acetzlacetonate chromium h acetyiacetonate cupric acetate, glycine cupric salt, cupric stearate, cupric bismuth trioxid (Bi 0 cuprous chloride a mixture oleate, cupric tartrate, cupric citrate, dextro-levo malic cuprous chloride y triethylamine a of tetra acid copper salt, cupric oxalate, bis (ethyl acetoacetate) cyanoquinomethane a mixture of cuprous chloride and P (l. phenyl l3'Butane'dlone) copper cupric copper (ll) acetylacetonate, a mixture of copper formate dimethyl dlthiocarbamate, cuprous sulfate B naphthol, and cuprous chloride cupric sulfate cupric chloride aFetylacetonfne Silver benzotriazolefi tin hydrated with two water molecules, cuprous bromide, mckel f q f w chlonfie" mckefl cuprous iodide, cupric bromide, cuprous sulfite, cupric sulfate, nickel fluoride, silver nitrate, silver oxide and trithiocyanate, cuprous sulfide cupric molybdate, cupric Phenyleneand a lower alcohol havmg chafn lactate, cupric formate copper p-toluene' sulfinite, cupric length of from 1 8 Whlch f reduction salicylate, cupric linoleate, cupric acetate, glycine cupric background nucleanon of the medmm upon develop salt, cupric stearate,cupric oleate,cupric tartrate, cupric Infant; and citrate, dextro-levo malic acid copper salt, cupric oxalate, coating the dispersed mixture onto a substrate prior to subbis (ethyl acetoacetate) copper, bis (1 Pheny1 stantial evaporation said solvent and said alcohol. tanedione) copper, cupric dimethyl dithiocarbamate The Process of clalm 10 where!" Said formmg p cuprous sulfate B napthol, cuprous acetylacetonate, silver cludes substantial evaporation of said solvent and said alcohol. benzotriazole, tin chloride, nickel chloride, chromium The Prom?SS of Producing a nucleation recording medi chloride, nickel sulfate, nickel fluoride, silver nitrate, with an image thereon comprises the Steps of: silver oxide and tri-phenylene and, a liquid lower alcohol dispersing together a resinous film-forming binder, an having a chain length from 1 to 8 to reduce background tinic ray sensitive compound selected from the group l i consisting of oxides of titanium, tantalum indium gforming a film of said dispersion, including evaporation of n germanium, Zinc, iron, tin and bismuth, sulfides substantially all of both said solvent and said alcohol; of calcium, Zin admi m n i m, and boron nitride, imagewise exposing said film to actinic radiation to form a Calcium tungstate, beryllium aluminide, lithium latent image of nucleation sites in accordance with the bonate, zinc carbonate, cadmium niobate, lithium imagewise exposure; niobate, calcium-magnesium silicate (cesium-activated) exposing said film to metal vapor under such conditions that and mixtures thereof, a solvent for said film-forming metal vapor deposits upon the nucleation sites to form a binder, a nucleation-inducing metallic salt selected from visible image.

(33 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 0,087 Dated y 1972 Invent0r(s) Alfred 'F. Kaspaul, Erika E. Kaspaul It is certified that error appears in the above-identified patent and that: said Letters Patent are hereby corrected as shown below:

Column 5, line 58, delete "means" and insert mean-. (page 14, line 12) Column 10, in the table under "100", insert 75 (page 26, line 19) Column 13, line 64, after "Example'NoJ', insert'-34-. (page 36, line 1) Column 14, line 3, delete "Zn(C H.' BE2) and substitute Zn(C H O (page 36, line 13) Column 17, line 70, delete "brightnezr" and insertbrightener-.-. (page .47, line 10 1/2) flflwmdflfidfl ade- Column 21, line-l, delete "reel" and insert real. (page 55, line 20) Column 23, line 1.6, delete "claim a" and substitute claim 7-. (Page 8, claim 13, Amendment 5/25/71) Signedand seal-ed this 27th day of February 1973..

(SEAL) Attesti EDWARD MQFLETCHERJR.

ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents 'zg gm UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. ,660,087 Dated y 1972 Inventor(s) Alfred 'F. Kaspaul, Erika E. Kaspaul It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 5, line 58, delete "means" and insert mean-. (page 14, line 12) Column 10, in the table under "100", insert --75-. (page 26, line 19) Column 13, line 64, after "Example No." insert '-34-. (page 36, line 1) Column 14, line 3, delete "Zn(C H; BE2) and substitute -Zn(C H O (page 36, line 13) Column 17, line 70, delete "brightner" and insert- -brightener.-. (page 47, line 10 1/2) mtflww Column 21, linel, delete "reel" and insert -real. (page 55, line 20) Column 23, line 16, delete claim 8" and substitute -claim 7-. (Page 8, claim 13, Amendment 5/25/71) Signed and seal-ed this 27th. day of February 19 73..

(SEAL) Attesti EDWARD MJ LETCHERJR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents 

2. The nucleation-recording medium of claim 1 wherein said metallic salt is a copper salt.
 3. The recording medium of claim 2 wherein said copper salt is selected from the group consisting of copper halides and copper organic salts.
 4. The nucleation-recording medium of claim 3 wherein said copper salt is selected from the group consisting of copper salts of lower organic fatty acids, copper lactate and copper acetylacetonate.
 5. The nucleation recording medium of claim 1 wherein said medium is coated upon an electrically conductive backing member.
 6. The nucleation recording medium of claim 4 wherein said metallic salt is cupric lactate.
 7. A nucleation-recording medium produced by the process including the step of dispersing together: a resinous film-forming vehicle; a solvent for said vehicle; an actinic ray sensitive material comprising a compound selected from the group consisting of oxides of titanium, tantalum, indium, magnesium, germanium, zinc, iron, tin and bismuth, sulfides of calcium, zinc, cadmium and indium, and boron nitride, calcium tungstate, beryllium aluminide, lithium carbonate, zinc carbonate, cadmium niobate, lithium niobate, calcium-magnesium silicate (cesium-activated) and mixtures thereof; a nucleation-inducing metallic compound selected from the group consisting of copper halide, copper (II) acetylacetonate, nickel (II) acetylacetonate, zinc (II) acetylacetonate, chromium (III) acetylacetonate, bismuth trioxide (Bi2O3), cuprous chloride, a mixture of cuprous chloride and triethylamine salt of tetra cyanoqUinomethane, a mixture of cuprous chloride and copper (II) acetylacetonate, a mixture of copper formate and cuprous chloride, cupric sulfate, cupric chloride hydrated with two water molecules, cuprous bromide, cuprous iodide, cupric bromide, cuprous sulfite, cupric thiocyanate, cuprous sulfide, cupric molybdate, cupric lactate, cupric formate, copper p-toluene sulfinite, cupric salicylate, cupric linoleate, cupric acetate, glycine cupric salt, cupric stearate, cupric oleate, cupric tartrate, cupric citrate, dextro-levo malic acid copper salt, cupric oxalate, bis (ethyl acetoacetate) copper, bis (1-phenyl 1,3-Butane-dione) copper, cupric dimethyl dithiocarbamate, cuprous sulfate B naphtol, cuprous acetylacetonate, silver benzotriazole, tin chloride, nickel chloride, chromium chloride, nickel sulfate, nickel fluoride, silver nitrate, silver oxide and tri-phenylene; and a liquid alcohol having a chain length of 1 to
 8. 8. The nucleation-recording medium of claim 8 wherein said metallic compound is copper lactate.
 9. The nucleation recording medium of claim 7 wherein said medium is coated upon an electrically conductive backing member.
 10. The process of forming an image medium upon which an image can be formed by nucleation recording, comprising the steps of: dispersing together a resinous film-forming vehicle, a solvent which dissolves the film-forming vehicle, a compound which is sensitive to actinic rays selected from the group consisting of oxides of titanium, tantalum, indium, magnesium, germanium, zinc, iron, tin and bismuth, sulfides of calcium, zinc, cadmium and indium, and boron nitride, calcium tungstate, beryllium aluminide, lithium carbonate, zinc carbonate, cadmium niobate, lithium niobate, calcium-magnesium silicate (cesium-activated) and mixtures thereof, a nucleation-enhancing metal salt selected from the group consisting of copper halide, copper (II) acetylacetonate, nickel (II) acetylacetonate, zinc (II) acetylacetonate, chromium (III) acetylacetonate, bismuth trioxide (Bi2O3), cuprous chloride, a mixture of cuprous chloride and triethylamine salt of tetra cyanoquinomethane, a mixture of cuprous chloride and copper (II) acetylacetonate, a mixture of copper formate and cuprous chloride, cupric sulfate, cupric chloride hydrated with two water molecules, cuprous bromide, cuprous iodide, cupric bromide, cuprous sulfite, cupric thiocyanate, cuprous sulfide, cupric molybdate, cupric lactate, cupric formate, copper p-toluene sulfinite, cupric salicylate, cupric linoleate, cupric acetate, glycine cupric salt, cupric stearate, cupric oleate, cupric tartrate, cupric citrate, dextro-levo malic acid copper salt, cupric oxalate, bis (ethyl acetoacetate) copper, bis (1-phenyl 1,3-Butane-dione) copper, cupric dimethyl dithiocarbamate, cuprous sulfate B naphthol, cuprous acetylacetonate, silver benzotriazole, tin chloride, nickel chloride, chromium chloride, nickel sulfate, nickel fluoride, silver nitrate, silver oxide and tri-phenylene, and a lower liquid alcohol having a chain length of from 1 to 8 which causes reduction in background nucleation of the medium upon development; and coating the dispersed mixture onto a substrate prior to substantial evaporation said solvent and said alcohol.
 11. The process of claim 10 wherein said forming step includes substantial evaporation of said solvent and said alcohol.
 12. The process of producing a nucleation recording medium with an image thereon comprises the steps of: dispersing together a resinous film-forming binder, an actinic ray sensitive compound selected from the group consisting of oxides of titanium, tantalum, indium, magnesium, germanium, zinc, iron, tin and bismuth, sulfides of calcium, zinc, cadmium and indium, and boron nitride, calcium tungstate, beryllium aluminide, lithium carbonate, zinc carbonate, cadmium niobate, lithium niobate, calcium-magnesium silicate (cesium-activated) and mixtures tHereof, a solvent for said film-forming binder, a nucleation-inducing metallic salt selected from the group consisting of copper halide, copper (II) acetylacetonate, nickel (II) acetylacetonate, zinc (II) acetylacetonate, chromium (III) acetylacetonate, bismuth trioxide Bi2O3), cuprous chloride, a mixture of cuprous chloride and triethylamine salt of tetra cyanoquinomethane, a mixture of cuprous chloride and copper (II) acetylacetonate, a mixture of copper formate and cuprous chloride, cupric sulfate, cupric chloride hydrated with two water molecules, cuprous bromide, cuprous iodide, cupric bromide, cuprous sulfite, cupric thiocyanate, cuprous sulfide, cupric molybdate, cupric lactate, cupric formate, copper p-toluene sulfinite, cupric salicylate, cupric linoleate, cupric acetate, glycine cupric salt, cupric stearate, cupric oleate, cupric tartrate, cupric citrate, dextro-levo malic acid copper salt, cupric oxalate, bis (ethyl acetoacetate) copper, bis (1-phenyl 1,3-Butane-dione) copper, cupric dimethyl dithiocarbamate, cuprous sulfate B naphthol, tin chloride, nickel chloride, chromium chloride, cuprous acetylacetonate, silver benzotriazole, nickel sulfate, nickel fluoride, silver nitrate, silver oxide and tri-phenylene and a liquid alcohol having a chain length from 1 to 8 to reduce background nucleation; forming a film of said dispersion, including evaporation of substantially all of both said solvent and said alcohol; imagewise exposing said film to actinic radiation to form a latent image of nucleation sites in accordance with the imagewise exposure; exposing said film to metal vapor under such conditions that metal vapor deposits upon the nucleation sites to form a visible image.
 13. The process of producing a nucleation-recording medium with an image thereon comprises the steps of: dispersing together a resinous film-forming binder, an actinic ray sensitive compound selected from the group consisting of oxides of titanium, tantalum, indium, magnesium, germanium, zinc, iron, tin and bismuth, sulfides of calcium, zinc, cadmium and indium, and boron nitride, calcium tungstate, beryllium aluminide, lithium carbonate, zinc carbonate, cadmium niobate, lithium niobate, calcium-magnesium silicate (cesium-activated) and mixtures thereof, a solvent for said film-forming binder, a nucleation-inducing metallic salt selected from the group consisting of copper halide, copper (II) acetylacetonate, nickel (II) acetylacetonate, zinc (II) acetylacetonate, chromium (III) acetylacetonate, bismuth trioxide (Bi2O3), cuprous chloride, a mixture of cuprous chloride and triethylamine salt of tetra cyanoquinomethane, a mixture of cuprous chloride and copper (II) acetylacetonate, a mixture of copper formate and cuprous chloride, cupric sulfate, cupric chloride hydrated with two water molecules, cuprous bromide, cuprous iodide, cupric bromide, cuprous sulfite, cupric thiocyanate, cuprous sulfide, cupric molybdate, cupric lactate, cupric formate, copper p-toluene sulfinite, cupric salicylate, cupric linoleate, cupric acetate, glycine cupric salt, cupric stearate, cupric oleate, cupric tartrate, cupric citrate, dextro-levo malic acid copper salt, cupric oxalate, bis (ethyl acetoacetate) copper, bis (1-phenyl 1,3-Butane-dione) copper, cupric dimethyl dithiocarbamate, cuprous sulfate B napthol, cuprous acetylacetonate, silver benzotriazole, tin chloride, nickel chloride, chromium chloride, nickel sulfate, nickel fluoride, silver nitrate, silver oxide and tri-phenylene and, a liquid lower alcohol having a chain length from 1 to 8 to reduce background nucleation; forming a film of said dispersion, including evaporation of substantially all of both said solvent and said alcohol; imagewise exposing said film to actinic radiation to form a latent image of nucleation sites in accordance with the imagewise exposure; exposing said film to metal vapor under suCh conditions that metal vapor deposits upon the nucleation sites to form a visible image. 